1. Field of the Invention
This invention relates to marine floats, and more particularly, to a structure for slidably securing marine floats to a marine pile.
2. Description of the Prior Art
Interconnected marine floats are commonly used to form marinas, docks, piers and the like. Various structures must be used to maintain the floats in position since the floats are subjected to forces exerted by currents and tidal changes. One very commonly used technique involves driving marine piles into the sea floor so that they project vertically from the surface of the water in which the floats are placed. Circular structures known as "pile hoops" are placed around the piles and secured to the floats. The hoops loosely surround the piles to allow the floats to rise and fall responsive to tidal changes while limiting the horizontal movement of the floats. Such pile hoops are most typically found at the ends of mainwalk and finger floats, but they may also be positioned in spaced-apart locations along the sides of the mainwalk and finger floats.
A variety of structures are used to secure the pile hoops to the ends of floats, none of which are entirely satisfactory. In one variety of pile hoop, the hoop projects from a flat plate having several holes formed therein through which bolts or inserts imbedded in the float project. The plate is then secured to the float by threading nuts onto the imbedded bolts or inserts. The principal disadvantage of this fastening structure arises from inadequately anchoring the inserts in the float. Most marine floats used with this pile hoop mounting structure are formed by a casing of concrete surrounding a buoyant foam billet. The bolts or inserts do not extend into the concrete for any great distance and are thus easily pulled out by side loads exerted on the float. The inserts may also be pulled out of the float by applying excessive torque to the fastening nuts, or when a pile is not entirely vertical so that it exerts transverse loads on the pile hoop as the hoop slides along the length of the pile. Once the inserts have been pulled out of a float, repair is not possible and the float must be replaced.
A second type of pile hoop mounting structure utilizes a wrap-around mounting plate to which the pile hoop is secured. The wrap-around plate is basically an end plate extending transversely across the end of a float having a pair of side plates projecting perpendicularly therefrom along the sides of the float. Tie rods extending transversely through the float project through respective apertures formed in the side plates to secure the side plates to the float. This mounting structure is far superior to the imbedded-insert structure since it utilizes tie rods which extend completely through the float. However, it is relatively expensive since it uses more material and requires substantially more fabricating and welding effort. Additionally, it is difficult for the side plates to suitably interface with elongated wood wales which typically extend along the upper side edges of the floats to interconnect one float to another. If the wales are to be placed along the outside surface of the side plates, either the float or the wales must be notched to allow the side plates to extend around the sides of the float. If the side plates are placed along the outside surface of the wales, the rigid corners between the end plate and the side plates can potentially damage vessels tieing up at the float. While resilient bumpers can be secured to the corners and side plates, this only adds to the relatively high cost of this type of pile hoop. Additionally, the floats are often not fabricated with a great deal of precision so that the fit between the pile hoop mounting structure and the float is not always satisfactory. Finally, this mounting structure is usually not satisfactory for fairly wide floats because the mounting plate is secured only at its ends. The large span resulting from use of this structure on wide floats allows the mounting plate to bend responsive to transverse forces exerted between the pile and the float.
While pile hoops are thus a highly satisfactory structure for slidably securing marine floats to piles, it is apparent that neither of the above-described mounting structures are both sufficiently inexpensive and sufficiently sturdy.